In order to arrange the flat plug tongues in a row on the base rail in as close a sequence as possible, two mutually differently profiled sheet-metal strips were used in the case of the known potential distributor of this type, which sheet-metal strips have the stamped and bent flat plug tongues in a mutually alternating sequence on the same longitudinal edge. Once the stamping and bending have been completed, the two strips are placed one on top of the other and are held together by brackets which are integrally formed on the bottom strip. These two strips which are placed one on top of the other produce a double-layer base rail from which the flat plug tongues originate in an alternating sequence, either from the upper layer or from the lower layer. The provision of different bending tools for the two strip parts, the stamping and bending processes which have to be carried out separately and, finally, the assembly of the two stamped products are cumbersome and time consuming. Despite the two strip parts being bracketed together, the two layers of the base rail do not make reliable electrical contact. In the event of movement and vibration, as necessarily occur when used in motor vehicles, undesirable spark flashovers can occur between the two layers of the base rail.
In the case of a contact piece having flat tongues (DE 41 09 013 A1), which has no two-layer flat base rail, it is known to proceed from a common sheet-metal strip on which the flat plug tongues are cut out in the two mutually opposite strip edges. The central zone of the common strip is folded to produce a U-shaped channel on whose two channel limbs the flat plug tongues are alternately integrally formed and are bent over the U-channel opening along an inclined folding line. Located on the respectively opposite U-channel limb is an edge cutout into which a lug, which is integrally formed on the flat plug tongues, must be clipped. These cumbersome bending and engagement processes are susceptible to defects and do not ensure that the flat plug tongues have a stable, correct position. Spark flashovers can also occur here, as a result of vibration. The U-channel rail permits only a limited electrical load capacity.
Single-layer potential distributors are known, in the case of which the flat plug tongues are produced by bending stamped-out lugs (DE-OS 30 23 341; DE-PS 30 48 451). In this case, the projecting flat plug tongues must be arranged at a relatively large distance apart. This does not permit compact construction. The single-layer nature of the base rail allows only a low electrical and mechanical load capacity.
It is known for the conductive contacts in the insulation housing of a contact strip to be produced from a U-shaped or double-U-shaped sheet-metal strip on whose two longitudinal edges mutually opposite attachments are stamped out which, after they have been bent, produce flat plug tongues (DE-OS 25 23 164). An extended base rail is not provided here. Finally, it is known for contact strips to be produced from a sheet-metal strip twisted into an S-shape, where individual limbs are extended on one side in order to produce projecting flat plug tongues there (FR-OS 21 09 583). A flat base rail is not provided here, for which reason the problem of being able to arrange flat plug tongues in a close sequence in such a linear structure does not arise.